Do Electrolytic Capacitors FREEZE?

On Sun, 6 Jan 2019 16:55:20 -0500, "Tom Del Rosso"
<fizzbintuesday@that-google-mail-domain.com> wrote:

>krw@notreal.com wrote:
>> On Sat, 05 Jan 2019 18:48:46 -0600, tubeguy@myshop.com wrote:
>>
>>> I have never known what the electrolyte is made from, inside of
>>> electrolytic capacitors. Is it a water based material, or oil based?
>>> If its water based, it will likely freeze if left outdoors in cold
>>> weather. For example, your car radio has caps, and if it's parked
>>> outdoors in the winter, the caps in it will freeze. Yet, I have never
>>> found my car radio working poorly in cold weather. This makes me
>>> believe the electrolyte must be oil based.....
>>>
>>> Does anyone know?
>>
>> Capacitors are rarely a problem in automotive applications. Automotive
>> applications are generally specified from -40C to +85C, ambient.
>> There are many capacitors to choose from that will satisfy that range.
>> Inductors tend to be more problematic (and easier to forget to derate
>> - and tend to make things explode).  Note that the electronics heats
>> fairly rapidly after the car is started so the lower end of the
>> temperature range is rarely a problem, particularly for infotainment
>> components.
>
>Why do inductors have an operating temperature range at all?

The permeability of the core material goes all to hell at both high
and low temperatures.  Also, insulation melts at high temperature
(RoHS was a RPITA for a while).  Lower inductance can cause switching
regulators to get really pissed (current goes to infinity as
inductance goes to zero).

On Monday, January 7, 2019 at 2:04:02 PM UTC+11, k...@notreal.com wrote:
> On Sun, 6 Jan 2019 16:55:20 -0500, "Tom Del Rosso"
> <fizzbintuesday@that-google-mail-domain.com> wrote:
> 
> >krw@notreal.com wrote:
> >> On Sat, 05 Jan 2019 18:48:46 -0600, tubeguy@myshop.com wrote:
> >>
> >>> I have never known what the electrolyte is made from, inside of
> >>> electrolytic capacitors. Is it a water based material, or oil based?
> >>> If its water based, it will likely freeze if left outdoors in cold
> >>> weather. For example, your car radio has caps, and if it's parked
> >>> outdoors in the winter, the caps in it will freeze. Yet, I have never
> >>> found my car radio working poorly in cold weather. This makes me
> >>> believe the electrolyte must be oil based.....
> >>>
> >>> Does anyone know?
> >>
> >> Capacitors are rarely a problem in automotive applications. Automotive
> >> applications are generally specified from -40C to +85C, ambient.
> >> There are many capacitors to choose from that will satisfy that range.
> >> Inductors tend to be more problematic (and easier to forget to derate
> >> - and tend to make things explode).  Note that the electronics heats
> >> fairly rapidly after the car is started so the lower end of the
> >> temperature range is rarely a problem, particularly for infotainment
> >> components.
> >
> >Why do inductors have an operating temperature range at all?
> 
> The permeability of the core material goes all to hell at both high
> and low temperatures.  Also, insulation melts at high temperature
> (RoHS was a RPITA for a while).  Lower inductance can cause switching
> regulators to get really pissed (current goes to infinity as
> inductance goes to zero).

Inductance doesn't go to zero. Air-cored coils still have some inductance.

Core materials do have a Curie point temperature (Marie Curie's husband) and if they get hotter than that they stop being ferromagnetic.

Cooling has less dramatic effect.

-- 
Bill Sloman, Sydney

>We have -50C freezer at work that we have test to see if products
>start up down around -40C/F  and they did after a couple of >fixes...
>BUT they (PV charge controller) weren't ran at any power.
>
>What I would like to try is to place an electrolytic or two or >three
>in there and bring out wires to be able to test this at say, >-50C."

Now is that 40 C or F ! Be specific ! (LOL)

Actually whatever you need to work at 50C is probably more extreme than what would  need to be looked at here. A regular food freezer can do 0F, we are at what, about -18C ? That makes me want to just stick a cap in an ice cube tray and measure it right when it comes out. Once the ice starts to melt I know it is at 0C. I think I have a freezer thermometer around here somewhere. 

What would be nice, though I am not sure about how useful, would be to isolate the ESR component from the capacitive drop component at the lower temperatures. they would affect the circuit, especially a regulation loop a bit differently. 

Sounds like an interesting thing to so just for the hell of it. 

Actually with your freezer at work you can do it with an ice cube anyway, though it  may have to be big for a bigger cap. It would hold its temperature long enough to get a reading because of the thermal mass of the H2O. How long does it take to measure ESR and capacitance ? Then if you want, with a thermometer you could plot it as it slowly comes up to ambient. You would have plenty of time. 

I don't know how much lower I could go than 0F. My freezers are set COLD, but they are newer ones and won't do -25F like some of the old overpowered monstrosities of the past. Plus they are full so it would take forever to get them to change. 

AHA, I just notice me old thermometer, goes down to -60F. I just stuck it in a freezer to see what it reads. Tomorrow I should know.

On Mon, 7 Jan 2019 02:42:02 +0000 (UTC),
DecadentLinuxUserNumeroUno@decadence.org wrote:

>"Tom Del Rosso" <fizzbintuesday@that-google-mail-domain.com> wrote in 
>news:q0ttt0$6kh$1@dont-email.me:
>
>> Why do inductors have an operating temperature range at all?
>> 
>
>  In the cold end they vary very little.  In high temps a few things 
>can happen.  One is that the transformer varnish it was likely vacuum 
>encapsulated in will liquify at some point.

Wrong.
>
>  For HV applications, this can pose an arcing potential issue.  Not 
>likely but an operating range has to be stated, and it will likely be 
>well below the melt point of any polymers or varnishes used in its 
>make-up.

Wrong.
>
>  This refers to miniature form factors of course.  Huge oil bath power 
>transformers are made with paper products and few polymers.  There are 
>plenty of isolation transformers, etc. and other designs where high 
>temps pose no problem far higher than those a circuit board sized 
>miniature can withstand.

AlwaysWrong.

On Sun, 6 Jan 2019 19:44:23 -0800 (PST), jurb6006@gmail.com wrote:

>>We have -50C freezer at work that we have test to see if products
>>start up down around -40C/F  and they did after a couple of >fixes...
>>BUT they (PV charge controller) weren't ran at any power.
>>
>>What I would like to try is to place an electrolytic or two or >three
>>in there and bring out wires to be able to test this at say, >-50C."
>
>Now is that 40 C or F ! Be specific ! (LOL)
>
>Actually whatever you need to work at 50C is probably more extreme than what would  need to be looked at here. A regular food freezer can do 0F, we are at what, about -18C ? That makes me want to just stick a cap in an ice cube tray and measure it right when it comes out. Once the ice starts to melt I know it is at 0C. I think I have a freezer thermometer around here somewhere. 
>
>What would be nice, though I am not sure about how useful, would be to isolate the ESR component from the capacitive drop component at the lower temperatures. they would affect the circuit, especially a regulation loop a bit differently. 
>
>Sounds like an interesting thing to so just for the hell of it. 
>
>Actually with your freezer at work you can do it with an ice cube anyway, though it  may have to be big for a bigger cap. It would hold its temperature long enough to get a reading because of the thermal mass of the H2O. How long does it take to measure ESR and capacitance ? Then if you want, with a thermometer you could plot it as it slowly comes up to ambient. You would have plenty of time. 
>
>I don't know how much lower I could go than 0F. My freezers are set COLD, but they are newer ones and won't do -25F like some of the old overpowered monstrosities of the past. Plus they are full so it would take forever to get them to change. 
>
>AHA, I just notice me old thermometer, goes down to -60F. I just stuck it in a freezer to see what it reads. Tomorrow I should know.


We had a regular chest freezer we used for a while.  Disabling the
thermostat and adding dry ice too it would go to ALMOST -40 !  About
-37C.  Right in that it doesn't really need to be measured to less
than -40 per usual specifications BUT we have had a customer in Alaska
that would prefer the units to run down to -50C  I think he said.
Fairbanks area.

Just for the hell of it would be correct